He paralyzes the Joker leaving him to die with a bomb to go off mocking him that Batman never laughed at his jokes because he sucks at being funny, and he's the biggest disgrace to clowns everywhere, and they voted him as the worst clown of all time. Oh one more thing he also tells him the robot clown in Happy Gilmore will also be funnier than him, and he was able to make lots of people laugh with minimum effort with one appearnce, while Joker failed more than a thousand times trying to hard.